I typically set up 2 types of protections when it comes to wireless security: encryption and mac-address filter (permission only for those who are listed). Recently, I noticed that there are wireless devices connected to my home router that I do not recognize. To be certain, I removed the mac address of my own cell phone from the router's mac-address filter, rebooted the router, and yet my phone was able to connect to the network wirelessly.

sorry for my previous, premature, post. It turned that those wireless devices were connected through another tomato router acting as a wires client bridge. I've applied mac address filter on both routers and now my network is secured.